The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Known hybrid powertrain systems use internal combustion engines and torque machines to generate tractive torque that may be transferred to a driveline via a transmission device. Known torque machines including electric motor/generator devices, hydro-mechanical devices, and other machines that convert stored energy to mechanical torque.
Known hybrid powertrain systems operate in either a charge-sustaining configuration or a charge-depleting configuration with regard to energy storage devices. Known hybrid powertrain systems include controlling the internal combustion engine using autostart and autostop control schemes. Known torque machines have limited output torque capability. Known hybrid powertrain systems preferentially use the torque machines to generate tractive torque when commanded output torque is less than the output torque capability of the torque machines and a state of charge of the energy storage device is greater than a threshold. As such, a hybrid powertrain system may operate under conditions wherein vehicle operation may not include an engine-on condition during an entire key-on cycle, so long as a commanded torque output does not exceed a threshold and a state of charge of the energy storage device is greater than a minimum threshold.